Scintillators are widely used detectors for spectroscopy of energetic photons. These detectors are commonly used in nuclear and high energy physics research, medical imaging, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. Important properties for the scintillation crystals used in these applications include high light output, fast response, low cost, good proportionality and minimal afterglow. There is continued interest in the search for scintillator materials that have one or more of these properties.